The nature of receptors on mammalian cells for B. pertussis and its adhesins is currently being investigated. Results indicate that virulent strains of B. pertussis can bind to certain glycolipids present in lung tissues. The structure of these glycolipids is being investigated as is the nature of the bacterial adhesins mediating this interaction. The role of integrins as receptors for the RGD-containing B. pertussis proteins, pertactin and FHA, is also under investigation. Our studies suggest that FHA may contain a lectin site that interacts with sulfated glycolipids, cell surface receptors which are present in large quantitites in human trachea and lungs. We are currently mapping this lectin binding site on the FHA molecule.